It was a valid reason but according to former Mozilla Firefox developer, Brian R. Bondy, he dives into a more detailed explanation as to why Mozilla killed off Firefox for the Metro UI, and that he believes Mozilla ultimately made the right decision in killing off the project.
According to Bondy, the problems are two fold. The first is that Microsoft does not allow browsers to run in the Modern UI mode unless it has been set as the default browser for the operating system. By default Internet Explorer has been set as the default browser, meaning that unless the user knows about changing browser defaults, Firefox for the Modern UI would have been moot.
He also states that Microsoft has made it a lot more harder and more confusing when it comes to switching browser defaults. If you run Windows 7, you will notice you will be prompted when you install/launch a new browser if you want to make it a default. However with Windows 8, the steps needed to make your browser the default browser is a little more complicating.
Bondy admits that the Modern UI is actually pretty important especially when it comes to touch hardware and that it is something people are slowly adopting, but for now he agrees that Mozilla made the right call to kill off the project. What do you guys think? Do you agree that the complexity of Windows 8 might put off more novice users and developers from adopting the Modern UI?